The present application is related to vehicle measurement or inspection systems, and in particular, to a vehicle inspection or measurement system configured to utilize displacement sensors to acquire measurement data associated with various surfaces on a vehicle as the vehicle moves through a vehicle inspection lane, and to identify specific features of the vehicle from the acquired measurement data.
Vehicle wheel alignment systems have utilized a variety of techniques for non-contact measurement of stationary vehicle wheel assembly parameters, from which vehicle wheel alignment angles can be determined. For example, by utilizing multiple displacement measurement sensors, displacement measurements between known sensor locations and multiple locations on a stationary vehicle wheel assembly can be measured. Processing acquired measurements from displacement sensors observing wheels on opposite sides of an axle can identify planes parallel to the wheel assembly surfaces, from which representations of total toe and camber angles for the vehicle can be determined. In other configurations, two-dimensional images of a stationary vehicle wheel assembly can be acquired, and image processing algorithms utilized to identify geometric features such as the wheel rim edge, from which a perspective analysis can be performed to determine estimates of vehicle wheel assembly spatial position and orientation. Alternatively, structured light patterns, such as multiple laser lines, or colored stripes, can be projected onto a stationary wheel assembly surface and observed by an imaging system. Deviations in the projected pattern are analyzed to generate representations of the illuminated surfaces, from which vehicle wheel assembly spatial position and orientation can be estimated. These systems generally require the vehicle to remain stationary relative to the sensors during the measurement acquisition procedure, but some non-contact measurement systems require either the wheel assembly or the sensors be rotated about a stationary axis of rotation during the measurement acquisition procedure in order to obtain sufficient measurement data.
A few measurements systems are configured to acquire measurements as a vehicle wheel assembly is both rotated and translated past the sensors, i.e., as the vehicle is moved past the sensors. For example, using a laser displacement sensor to measure a distance between a fixed sensor and various points on a vehicle wheel assembly as a vehicle is driven past the sensor at a slow speed, enables a non-contact system to acquire measurement data along a horizontal slice of the wheel assembly, from which an approximation of the wheel spatial orientation can be derived. These types of non-contact systems are highly influenced by the speed at which the vehicle travels between the individual sensors, the angle (straightness) of vehicle travel relative to the sensor observation axis, suspension movement, surface features of the wheel assembly at the point of measurements (i.e., tire lettering, bulges, runout, valve stems, etc.) and changes in steering of the vehicle as it passes the sensor. Measurements acquired from a moving vehicle are useful to provide a vehicle service quick check or audit inspection, capable of identifying vehicles which may be in need of a further, more precise, alignment inspection and/or adjustment.
Accordingly, it would be beneficial to the vehicle service quick check or inspection industry if additional vehicle measurements could be acquired as the vehicle is driven, such as by a customer, through a sensing region of a vehicle inspection lane, and if variations in vehicle speed, steering, suspension movement, or direction of travel could be identified and/or accounted for during the acquisition of measurements associated with the moving vehicle.
It would be further advantageous to provide a method by which the acquired measurements could be evaluated to identify specific features of the vehicle based on the contours of observed surfaces which move past the measurement sensors.